This invention relates to the field of door securement devices. More particularly, the present invention relates to door latches particularly suitable for employment with locker doors.
Lockers are purchased by a number of businesses to store employee supplies of various types, uniforms, and employee clothing. Very often, the lockers include a cylinder lock of relatively inexpensive construction. Examples of a typical lock are included in the drawing to this application in FIGS. 2 and 4. Although some manufacturers allegedly try and promote the security of lockers having this type of cylinder lock, the lockers are not in fact very secure and both the employer and employees typically avoid placing anything of value in the locker. Unfortunately, the cylinder locks are prone to malfunction and frequently prevent entry into the locker space. Additionally, employees will lose or forget to carry their key preventing easy entry. When the key is missing, if a master key is not available, the lock will have to be forced and then replaced. Similarly, when a lock malfunctions it will have to be replaced. The replacement generally causes considerable additional inconvenience and expense far in excess of the intrinsic value of the replacement lock.
FIG. 2 illustrates a typical cylinder lock 20 in an exploded view. Lock 20 includes five major components: key 22, cylinder 24, housing 26, bolt 28 and connector means 30. Cylinder 24 includes a plurality of tumblers 32, rotation stop 34, square 36 and thread 38. Cylinder 24 is received within housing interior surface 40.
Housing interior surface 40 includes at least one longitudinal tumbler groove 42 and housing stops 44. If key 22 is not inserted into cylinder 24, tumblers 32 protrude into tumbler grooves 42 to prevent relative rotation between cylinder 24 and housing 26. If a key is inserted into cylinder 24, tumblers 32 are withdrawn into the body of cylinder 24 to allow relative rotation with housing 26. However, this rotation is limited by the interaction between rotation stop 34 and housing stops 44 located at the front or exterior of housing 26. At least one housing flat 46 is provided to interface with corresponding flat on a door orifice to prevent relative rotation between housing 26 and the door. Additionally, at least one housing groove 48 is provided for receiving a tension clip to prevent longitudinal movement of housing 26 with respect to the door by restraining it between the tension clip and housing flange 50. Frequently, both the housing 26 and the cylinder 24 are fabricated from economical cast metal. Bolt 28 defines square orifice 52 in its exterior plane 54 and interfaces with a door frame at its interior plane 56. These exterior 54 and interior 56 planes are joined by offset portion 58. Bolt 28 is fitted over square 36 of cylinder 24 and fastened to cylinder 24 by connector means 30 consisting of star washer 60 and nut 62. Bolt 26, on its exterior plane 54, is brought to bear against the flat interior end 64 of housing 26.
Other locking devices for fastening doors to their frame are described in issued patents.
U.S. Pat. No. 3,876,237 to Hayes, Jr. et al. describes a LOCKING DEVICE incorporating tumbler lock 31 in handle portion 24. Crank assembly 21 consists of crank 21', a journal housing 23 and handle 24. The crank 21' is a metal rod with two 90 degree bends which allows one of the arms 25 to be journaled through the housing 23 and the other arm 26 to releasably engage receiver 22.
U.S. Pat. No. 4,270,780 to Bernard describes a DOOR FASTENER which may incorporate a standard shaft, a lock cylinder or a shaft having a head of a particular shape. A flanged bearing 2 is made longitudinally fast to a door with the aid of nut 13. A handle 14 includes pin 71 which is selectively received by bearing 2 in a position to allow relative rotation or prevent relative rotation. In FIG. 6, an embodiment is shown which includes lateral stop 67 moving in angular cutaway 69 formed at the end 68 of the bearing 2.
U.S. Pat. No. 4,186,952 to Glass describes a TURN BUTTON LATCH. The latch assembly 10 includes latch member 14 which cooperates with housing 16. Housing 16 in turn cooperates with retainer clip 18. Cylinder 60 is received within housing 16. Plate 62 including detent member 64 is placed between thumb latch 58 and cylinder 60 to cooperate with recesses 34-37. Bolt 20 is fastened to cylinder 60 through cooperation of arms 66 and 68 and pin 78. The embodiments of FIG. 12 include a locking cylinder.
Other fasteners described in patents dispense with locks.
U.S. Pat. No. 4,153,284 to Wright describes a PAWL LATCH. The Wright latch includes bush 1 and integral transverse channel shape extension 4. In head 2 an arrow shaped recess 7 points in the direction of the transverse channel to indicate the orientation of the latching arm or pawl which is partly formed by channel 4 but also by metal spring clip 8. Although principally fabricated from plastics, the latch is particularly useful to ensure electrical continuity of a wiring enclosure.
U.S. Pat. No. 4,105,230 to Amann et al describes a CLOSURE FOR PIVOTABLE FLAPS, COVERS OR THE LIKE. The closure includes locking member 4 which is approximately L-shaped and fastened to shaft 5 which receives a handle 11 to the opposite side of flap 10. A spring 6 is interposed between locking member 4 and flap 10. The closure does not appear to include a bushing or housing for shaft 5.
U.S. Pat. No. 1,662,907 to Shilling et al. describes a DOOR LATCH of relatively elaborate construction. In FIG. 5, a less elaborate embodiment is illustrated which includes a block 45 which longitudinally moves in and out of engagement with bars 20.
None of the foregoing describe or suggest a simple, economical device which avoids the drawbacks associated with the cylinder locks previously employed.